Buggy code:
public void setEnded ( boolean isEnded ) { } public void signal ( String signalName , Object signalData ) { } public void take ( PvmTransition transition ) { } public void take ( PvmTransition transition , boolean fireActivityCompletionEvent ) { } public void executeActivity ( PvmActivity activity ) { } public List < ActivityExecution > findInactiveConcurrentExecutions ( PvmActivity activity ) { } protected List < ExecutionEntity > getAllChildExecutions ( ) { } @ SuppressWarnings ( { "unchecked" , "rawtypes" } ) public void takeAll ( List < PvmTransition > transitions , List < ActivityExecution > recyclableExecutions ) { } protected void fireActivityCompletedEvent ( ) { } protected boolean allExecutionsInSameActivity ( List < ExecutionEntity > executions ) { } public void performOperation ( AtomicOperation executionOperation ) { } protected void performOperationSync ( AtomicOperation executionOperation ) { } protected void scheduleAtomicOperationAsync ( AtomicOperation executionOperation ) { } public boolean isActive ( String activityId ) { } public void inactivate ( ) { } public List < ExecutionEntity > getExecutions ( ) { } @ SuppressWarnings ( { "unchecked" , "rawtypes" } ) protected void ensureExecutionsInitialized ( ) { } public void setExecutions ( List < ExecutionEntity > executions ) { } public ExecutionEntity findExecution ( String activityId ) { } public List < String > findActiveActivityIds ( ) { } protected void collectActiveActivityIds ( List < String > activeActivityIds ) { } public String getBusinessKey ( ) { } public void setBusinessKey ( String businessKey ) { } public String getProcessBusinessKey ( ) { } public ProcessDefinitionImpl getProcessDefinition ( ) { } public void setProcessDefinitionId ( String processDefinitionId ) { } public String getProcessDefinitionId ( ) { } public String getProcessDefinitionKey ( ) { } public void setProcessDefinitionKey ( String processDefinitionKey ) { } public String getProcessDefinitionName ( ) { } public void setProcessDefinitionName ( String processDefinitionName ) { } public Integer getProcessDefinitionVersion ( ) { } public void setProcessDefinitionVersion ( Integer processDefinitionVersion ) { } public String getDeploymentId ( ) { } public void setDeploymentId ( String deploymentId ) { } protected void ensureProcessDefinitionInitialized ( ) { } public void setProcessDefinition ( ProcessDefinitionImpl processDefinition ) { } public ExecutionEntity getProcessInstance ( ) { } protected void ensureProcessInstanceInitialized ( ) { } public void setProcessInstance ( InterpretableExecution processInstance ) { } public boolean isProcessInstanceType ( ) { } public ActivityImpl getActivity ( ) { } protected void ensureActivityInitialized ( ) { } public void setActivity ( ActivityImpl activity ) { } public ExecutionEntity getParent ( ) { } protected void ensureParentInitialized ( ) { } public void setParent ( InterpretableExecution parent ) { } public String getSuperExecutionId ( ) { } public ExecutionEntity getSuperExecution ( ) { } public void setSuperExecution ( ExecutionEntity superExecution ) { } protected void ensureSuperExecutionInitialized ( ) { } public ExecutionEntity getSubProcessInstance ( ) { } public void setSubProcessInstance ( InterpretableExecution subProcessInstance ) { } protected void ensureSubProcessInstanceInitialized ( ) { } public String getRootProcessInstanceId ( ) { } public void setRootProcessInstanceId ( String rootProcessInstanceId ) { } protected ScopeImpl getScopeObject ( ) { } public boolean isScope ( ) { } public void setScope ( boolean isScope ) { } public void remove ( ) { } public void destroyScope ( String reason ) { } private void removeEventScopes ( ) { } private void removeEventSubscriptions ( ) { } private void removeJobs ( ) { } private void removeTasks ( String reason ) { } public ExecutionEntity getReplacedBy ( ) { } @ SuppressWarnings ( { "unchecked" , "rawtypes" } ) public void setReplacedBy ( InterpretableExecution replacedBy ) { } @ Override protected void initializeVariableInstanceBackPointer ( VariableInstanceEntity variableInstance ) { } @ Override protected Collection < VariableInstanceEntity > loadVariableInstances ( ) { } @ Override protected VariableScopeImpl getParentVariableScope ( ) { } protected ExecutionEntity getSourceActivityExecution ( ) { <START_BUG> return ( activityId ) != null ? this : null ; <END_BUG> } @ Override protected boolean isActivityIdUsedForDetails ( ) { } @ Override protected VariableInstanceEntity createVariableInstance ( String variableName , Object value , ExecutionEntity sourceActivityExecution ) { } @ Override protected void updateVariableInstance ( VariableInstanceEntity variableInstance , Object value , ExecutionEntity sourceActivityExecution ) { } @ Override protected VariableInstanceEntity getSpecificVariable ( String variableName ) { } @ Override protected List < VariableInstanceEntity > getSpecificVariables ( Collection < String > variableNames ) { } public Object getPersistentState ( ) { } public void insert ( ) { } public void deleteCascade ( String deleteReason ) { } public int getRevisionNext ( ) { } public void forceUpdate ( ) { } public EngineServices getEngineServices ( ) { } public String toString ( ) { } protected String getToStringIdentity ( ) { } public List < EventSubscriptionEntity > getEventSubscriptionsInternal ( ) { } public List < EventSubscriptionEntity > getEventSubscriptions ( ) { } public List < CompensateEventSubscriptionEntity > getCompensateEventSubscriptions ( ) { } public List < CompensateEventSubscriptionEntity > getCompensateEventSubscriptions ( String activityId ) { } protected void ensureEventSubscriptionsInitialized ( ) { } public void addEventSubscription ( EventSubscriptionEntity eventSubscriptionEntity ) { } public void removeEventSubscription ( EventSubscriptionEntity eventSubscriptionEntity ) { } @ SuppressWarnings ( { "unchecked" , "rawtypes" } ) protected void ensureJobsInitialized ( ) { } protected List < JobEntity > getJobsInternal ( ) { } public List < JobEntity > getJobs ( ) { } public void addJob ( JobEntity jobEntity ) { } public void removeJob ( JobEntity job ) { } @ SuppressWarnings ( { "unchecked" , "rawtypes" } ) protected void ensureTasksInitialized ( ) { } protected List < TaskEntity > getTasksInternal ( ) { } public List < TaskEntity > getTasks ( ) { } public void addTask ( TaskEntity taskEntity ) { } public void removeTask ( TaskEntity task ) { } public List < IdentityLinkEntity > getIdentityLinks ( ) { } public IdentityLinkEntity addIdentityLink ( String userId , String groupId , String type ) { } public IdentityLinkEntity involveUser ( String userId , String type ) { } public void removeIdentityLinks ( ) { }

Fix:
return this ;